Not everyone can justify building an acoustically treated, soundproof studio, but with a little effort and ingenuity, you can often make significant improvements to the room you already have at very little cost. Paul White presents a few ideas.
Here at SOS, we receive a great number of readers' queries — by letter, by e‑mail, and by phone — and one recurring theme is that of soundproofing and acoustic treatment. About a year ago, we ran a full series on studio construction, but if you don't have a separate room to use as a studio, or if you're living in rented accommodation, you may not be in a position to build a dedicated studio. In fact, it seems that many of you are working in a bedroom or in an untreated spare room, and what you're after is a few tips on how to cut down on noise leakage, while at the same time improve the monitoring acoustics.
I have to come clean at the outset and admit that there's no cheap and cheerful way to soundproof a room. The techniques I'll be talking about here can make a significant improvement, but there's no way you're going to be able to contain the sound of a drum kit or a serious studio monitor system turned up full bore. Anything short of a custom designed studio is a compromise, and if you're working in a typical domestic room, this means taking measures to reduce the amount of noise you actually produce as well as trying to reduce the amount of noise that leaks out.
Most home recording setups are based around MIDI systems and DI'd instruments, so most of the sound you generate will come from your monitor speakers. It's also true that floors and ceilings tend to be less solidly built than walls, and you'll find that most of your sound leakage occurs via floors, ceilings, windows, and doors. Partition walls may also leak sound badly, but unless you're prepared to build a heavy, false wall in front of the existing one, any improvements in this area can only be minor.
Since the monitor speakers are the source of the sound you're trying to contain, it makes sense to start with them. Obviously speakers are designed to launch sound into the air, but what with action and reaction being equal and opposite, every time the speaker cone moves, so does the speaker cabinet. Though small, this vibrational movement can be transmitted through the speaker stand (shelf, dressing table top or whatever) into the floor or wall, and once you have a vibration in the structure of the building, you have the potential for sound to leak into adjoining rooms.
There are several things you can do to minimise this problem. Firstly, don't use speakers with a massive bass response, because low frequencies are the hardest to contain. in a small or untreated room. Bass frequencies behave very unpredictably, so by choosing a speaker with a more modest bass response, you'll actually end up with a more accurate sound as well as reducing the amount of bass thumping through neighbouring walls.
Secondly, set up your monitors so you're working in the nearfield — in other words, with the monitors around one metre away from you and just a little more than that apart. Because sound intensity works according to the inverse square law (a fancy mathematical term for something being louder when you're closer to it!), the closer you are to your monitors, the less power you need to hear the same sound level. A further advantage of working in the nearfield is that you hear more of the direct sound from the speakers and less of the sound reflected from the walls and objects in the room, so you gain an increase in accuracy without actually doing anything at all to the room.
These techniques can make a significant improvement, but there's no way you're going to be able to contain the sound of a drum kit or a serious studio monitor system turned up full bore.
That still doesn't address the problem of structurally‑borne vibration, so what's needed here is some way of isolating the loudspeakers from the surfaces on which they normally stand. At one time, I recommended standing the speaker cabs on a piece of 50mm foam rubber, and I notice that Studiospares [Tel: 0171 482 1692] are now selling foam pads specifically designed for this purpose. The isolation could be improved even further by placing a small concrete slab (an excuse for visiting your local garden centre, if you're into that) on top of the foam and then standing the speaker on four lumps of Blu‑Tac on top of the slab.
Even with nearfield monitors, a significant amount of low frequency energy is still generated, and this is radiated in all directions — not just in the direction in which the speaker is pointing. That being the case, if you're worried about sound passing through a wall into the adjoining room, it's best to position the speakers as far away from that wall as possible.
Earlier on, I commented on the fact that sound tends to leak through ceilings and floors. Unless you want to get into major structural redesign, the best method to combat this is to fit thick, hair underfelt (the brown matted stuff, not foam rubber) underneath the carpet in your studio room (and beneath the carpet in the room above, if there is one). The combined weight and thickness of the carpet and underfelt provides both absorption and damping, so buy the heaviest grade possible. Also avoid tapping your feet to the music (yes, I know it's hard, but try) as this is often more annoying to the people below than the sound of your monitors!
If your room is fitted with plenty of soft furniture, you probably won't suffer any serious acoustic problems; but if you've had to clear out a lot of the furniture to make room for your equipment, you might find the room just a bit too live. The tradition studio solution is either to cover the walls with rockwool or hang heavy, pleated, velvet drapes along the back wall, but you can achieve similar results by hanging up an ordinary quilt on the wall facing your monitors. Another option is to buy two or three rag rugs (very cheap and immensely fashionable) and then hang these on the back wall, so that they are a couple of inches away from the wall's surface. It may also help to ensure that there are no hard, reflective surfaces directly to either side of your normal listening position; if there are, a couple of half metre, foam sound absorbing tiles fixed to the walls either side using double‑sided tape is usually enough to soak up any serious reflections and to kill any flutter echo. Once again, Studiospares carry a range of foam tiles. Sofas, beds, and armchairs are also useful allies in soaking up reflected sound.
So what about doors and windows? In most cases, these are the most vulnerable areas when it comes to sound leakage. If you don't have double‑glazed windows and you have a problem either with sound getting in or sound getting out, then secondary double‑glazing is highly recommended. DIY kits are available for a sensible price these days, and because the space between the original window and the secondary glazing is quite large, you'll often find that the amount of sound reduction is better than you'd get from conventional double‑glazing alone. If you have a choice of fitting different thicknesses of glass, use the thickest you can, because more mass equates to better low frequency isolation. A cheaper alternative, if daylight isn't a major consideration, is to build a heavy wooden shutter and screw it over the window. If you want to take it down between sessions, then use sash window fasteners to hold it in place.
Doors are rather less simple to deal with, because their mass is much lower than that of the surrounding walls. Fitting good quality draftproof seals will prevent sound leaking around the edge of the door, but a typical lightweight domestic internal door only provides something like 15dB of sound attenuation, even when it fits properly. Fitting heavy curtains over the door helps a little — but don't expect miracles.
Replacing the door with a heavy fire door will yield some improvement, but it's not until you start fitting double doors that you make any real headway against serious sound leakage. Providing the room adjoining your studio isn't inhabited while you're working, just fitting door seals should be fine — but don't expect to be able to monitor at full volume without upsetting someone, if the next room is occupied.
All the above measures are pretty straightforward to implement and all will bring about some improvement. Even so, you won't get anything like the sound isolation you'd expect from a properly‑built studio, so you may still have to keep an eye on your monitoring levels and stop work at a sensible time of night. It also helps to use headphones when you're composing or editing music; headphones aren't great for mixing, but providing you have a comfortable pair, you can use them in place of monitors quite a lot of the time.
Finally, don't underestimate diplomacy. Most neighbours will put up with a little noise if they don't think you're being inconsiderate to them. Try to agree times when your neighbours will let you monitor more loudly, and in return, agree not to make too much noise during the times they want a bit of peace and quiet. Whatever else you may think of MIDI, it has at least made it possible for us to compose and record music without having to shake the house.